JPH01194836A - Frostproofer for electric rotary machine - Google Patents

Abstract

PURPOSE:To reduce power necessary for frostproofing and to same power, by applying heat stored in a heat-exchanger onto the air at the outside of a frame, thereby lowering humidity. CONSTITUTION:When a rotary machine stops and the humidity in the machine exceeds a specific level, a humidity sensor 2 functions and the outer air is sucked into a frame 1. At this time, heat-exchange is made between the outer air and the liquid in a pipe 14, thus increasing the temperature of the outer air gradually toward a discharge port 7. Consequently, temperature difference between the outer air and the liquid in the pipe 14 is large at a point remote from the discharge port 7 while the difference is small at a position close to the discharge port 7. Temperature difference also occurs in the pipe 14 and the liquid is circulated as shown by an arrow C, thus transferring heat stored in upper and lower tanks 11, 12 effectively to the outer air. The heated outer air is sucked into the frame 1 to provide frostproof function, and since the thermal energy consumed for heating of the outer air is the loss energy produced during operation of the electric rotary machine, a quite small amount of defrost power is required for a vent fan 9.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a dew condensation prevention device while a rotating electric machine is stopped.

(Conventional technology) Rotating electrical machines generate heat during operation, resulting in high temperatures.

When the machine stops operating, it no longer generates heat, so it is cooled by the surrounding outside air, but if the surrounding humidity is high, such as in a climate under a tropical cyclone, condensation often forms on various parts of the rotating electrical machine. Rotating electric machines are constructed using many insulators, so if condensation occurs on the insulating parts, the insulation resistance decreases or the progress of insulation deterioration is accelerated, resulting in the machine becoming unable to operate.

For this reason, in general rotating electric machines, when the machine is stopped, a heater attached to the lower part of the frame is energized to raise the temperature inside the frame and lower the humidity to prevent condensation. With this method, electricity costs increase because the heater is energized while the rotating electrical machine is stopped, and because the internal structure of the rotating electrical machine is complex, each part of the rotating electrical machine is uniformly heated by natural convection of the air heated by the heater. There was a drawback that it was not. On the other hand, in Japanese Utility Model Application Publication No. 62-26165, as shown in FIGS. 4 and 5, the humidity inside the frame (1) is sensed by a humidity sensor (2) installed inside the frame (1), and When the temperature exceeds the value, the heater (4) and fan (5) in the fan heater box (3) are operated to send heated drying air into the frame (1), and the intake air shown by the solid line is drawn by the broken line. A proposal was made to change the exhaust air shown by the solid line to the exhaust air shown by the solid line and ventilate in the same direction to reduce the humidity inside the frame (1). Note that (6) and (7) are the intake and exhaust ports during operation. Although this seemed to be quite effective, it did not improve the electricity costs of heaters that originally used electrical energy with low conversion efficiency into heat energy, and was not a complete solution.

(Problem to be Solved by the Invention) In the conventional dew condensation prevention device for a rotating electric machine configured as described above, the heater (4) is energized only when the rotating electric machine is stopped and the humidity exceeds a specified value. Then, heated air is sent into the frame (1) to reduce the humidity inside the frame (1), but since the power supplied to the heater (4) is not originally required directly for the operation of the rotating electrical machine. However, the operating efficiency, which is expressed as the output relative to the input power, deteriorates accordingly, and contrary to the current trend toward energy-saving equipment, there has been a desire for a dew condensation prevention device that uses less power.

SUMMARY OF THE INVENTION An object of the present invention is to provide a dew condensation prevention device for a rotating electrical machine that reduces the amount of power required to prevent condensation and is energy saving oriented.

[Structure of the invention]

(Means for solving the problem) This will be explained using FIGS. 1 and 2. A heat exchanger (8) is attached to the exhaust port (7), and the heat loss generated during operation of the rotating electric machine is stored in the heat exchanger (8), and the single-rotation machine stops and the humidity inside the frame (1) is regulated. When the temperature exceeds the value, the ventilation fan (9) is operated in reverse, and the heat stored in the heat exchanger (8) is added to the air outside the frame (1), and the heat is supplied to the inside of the frame (1) to cool the frame. (1) Reduce the humidity inside.

(Function) Heat generated during operation of the rotating electric machine is stored in the heat exchanger (8) attached to the exhaust port (7). When the rotating electric machine stops and the humidity inside the frame (1) exceeds the specified value, the ventilation fan (
9) operates in reverse, but the heat stored in the heat exchanger (8) installed in place of the conventional heater raises the temperature of the outside air, providing a dew condensation prevention function without the need for electrical energy to be converted into thermal energy. be able to.

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 3. This embodiment is an example in which an inspection door (10) of a rotating electrical machine has an exhaust port (7). Liquid tanks (11) are provided above and below the outside of the exhaust port (7), and the liquid tanks (11), (1
2) is surrounded by a heat insulating material (13), and a heat exchanger (8) is installed in which the upper and lower liquid tanks (11) and (12) are connected with multiple pipes (14). Attach the humidity sensor (2). A ventilation fan (9) that can reverse the flow by reversing the airflow is provided at the intake port (6).

In the dew condensation prevention device for a rotating electrical machine configured in this way, when the rotating electrical machine is operated, the ventilation fan (9) closes the air intake (
6), outside air is forced in and ventilated to cool the heat generating part, and the heated air is discharged from the exhaust port (7) as shown by arrow A in Figure 3. The liquid inside exchanges heat, the temperature of the liquid rises, and it rises due to buoyancy as shown by arrow C in Figure 3 and enters the upper liquid tank (11). On the other hand, the air passing through the pipe (14) away from the exhaust port (7) undergoes heat exchange before reaching there, so the temperature is lower than the liquid temperature in the pipe (14) on the exhaust port (7) side. It circulates and both tanks (11) and (1
2) Heat is stored in the liquid. On the other hand, when the rotating electric machine stops and the humidity inside the machine exceeds the specified value, the humidity sensor (2) is activated.
The ventilation fan rotates in the opposite direction and sucks outside air into the frame (1) as shown by arrow B, but at this time the pipe (14)
It exchanges heat with the liquid inside to raise the temperature of the outside air, and the closer it gets to the exhaust port (7), the higher the temperature of the outside air becomes. Therefore, the temperature difference between the liquid in the pipe (14) far from the exhaust port (7) and the outside air is large, but the difference decreases near the exhaust port (7), so a temperature difference also occurs in the pipe (14), and the temperature difference in the pipe (14) is large. The liquid is circulated as shown by arrow C in Figure 3, and the liquid is transferred to the upper and lower liquid tanks (1
The heat stored in 1) and (12) is effectively exchanged with the outside air. The heated outside air is drawn into the frame (1) to provide a dew condensation prevention function, but the thermal energy used to heat the outside air is...

This is the heat loss generated during operation of the rotating electric machine, and this device can use extremely little power to prevent condensation by only operating the ventilation fan (9).

〔Effect of the invention〕

According to the present invention, the heat generated during operation is accumulated in the heat exchanger, and when the humidity exceeds the specified humidity at the time of stoppage, the accumulated heat is dissipated to raise the temperature of the outside air. It is possible to provide a dew condensation prevention device for a rotating electric machine that requires no electrical energy and requires only a very small amount of electric power to operate a ventilation fan.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a dew condensation prevention device 1'I for a rotating electric machine according to the present invention, and FIG. 2 is a schematic cross-sectional view taken along a vertical plane including the line n-■ in FIG. , FIG. 3 is an enlarged sectional view showing the heat exchanger shown in FIG. 2, FIG. 4 is a perspective view showing a conventional example, and FIG. 5 is a schematic view taken along the vertical plane including the line ■-■ in FIG. It is a diagram. 1...Frame, 2...Humidity sensor, 6
...Intake port, 7...Exhaust port, 8...
Heat exchanger, 9... Ventilation fan.

Claims (1)

[Claims] A ventilation fan provided in a ventilation path of a frame of a rotating electrical machine that allows reverse flow by reversing; a heat exchanger provided at an exhaust port of the frame; and a humidity sensor provided in the frame for controlling the ventilation fan in reverse. A dew condensation prevention device for a rotating electric machine, which is characterized by the following: